Silicon Laboratories SI2493/57/34/15/04 - Manual (Page 104)

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104 Rev. 1.3
Table 56. Register U4D Bit Map
Bit Name Function
15 Reserved Read returns zero.
14 TOCT Turn Off Calling Tone.
0 = Disable.
1 = Enable.
13 Reserved Read returns zero.
12 NHFP No Hook-Flash Pulse.
0 = Disable.
1 = Enable.
11 NHFD No Hook-Flash Dial.
0 = Disable.
1 = Enable.
10 CLPD Check Loop Current Before Dialing.
0 = Ignore.
1 = Check.
9 Reserved Read returns zero.
8 FTP Force Tone or Pulse.
0 = Disable.
1 = Enable.
7 SPDM Skip Pulse Dial Modifier.
0 = No.
1 = Yes.
6 Reserved Read returns zero.
5 GT18 1800 Hz Guard Tone Enable (UK Guard Tone)
0 = Disable.
1 = Enable.
4 GT55 550 Hz Guard Tone Enable.
0 = Disable.
1 = Enable.
3 CTE Calling Tone Enable.
0 = Disable.
1 = Enable.
2 Reserved Read returns zero.
1 Reserved Read returns zero.
0 Reserved Read returns zero.